IPA: /ˈjʌŋstər/
KK: /ˈjʌŋstər/
A young person, typically a child or teenager.
The youngsters played in the park after school.
Youngster → It is formed from "young" (from Old English "geong", meaning youthful or not old) and "-ster" (a suffix used to denote a person associated with a particular quality). The word "youngster" refers to a person who is young or youthful.
Think of someone who is 'youthful' ('young') and the '-ster' meaning a person. A youngster is simply a person who is young.